s 91 Assessments and additional assessments in certain cases
(1) The Director General, where for any year of assessment it appears to him that no or no sufficient assessment has been made on a person chargeable to tax, may in that year or within six years after its expiration make an assessment or additional assessment, as the case may be, in respect of that person in the amount or additional amount of chargeable income and tax or in the additional amount of tax in which, according to the best of the Director General’s judgment, the assessment with respect to that person ought to have been made for that year. (2) Where the Director General discovers that the whole or part of any tax repaid to a person (otherwise than in consequence of an agreement come to with respect to an assessment pursuant to subsection 101(2) or in consequence of an assessment having been determined on appeal) has been repaid by mistake whether of fact or law, the Director General may make an assessment in respect of that person in the amount of that tax or that part of that tax, as the case may be: Provided that no such assessment shall be made— (a) if the repayment was in fact made on the basis of, or in accordance with, the practice of the Director General generally prevailing at the time when the repayment was made; or (b) in respect of any tax, more than six years after the tax has been repaid. (3) The Director General where it appears to him that— (a) any form of fraud or wilful default has been committed by or on behalf of any person; or (b) any person has been negligent, in connection with or in relation to tax, may at any time make an assessment in respect of that person for any year of assessment for the purpose of making good any loss of tax attributable to the fraud, wilful default or negligence in question. (4) Where in a year of assessment— (a) any assessment made in respect of a person for any year of assesssment has been determined by the court on appeal or review; or (b) any exemption, relief, remission or allowance granted to a person for any year of assessment pursuant to any provision of this Act or any other written law in respect of income of that person which is subject to tax under this Act has been withdrawn, revoked or cancelled for failing to comply with any condition imposed in granting such exemption, relief, remission or allowance, the Director General may in the first mentioned year of assessment or within six years after its expiration make an assessment in respect of that person for any year of assessment for the purpose of giving effect to the determination, revocation, withdrawal or cancellation, as the case may be.